<template>
	<view class="content">
		<!--
		* 广告组件
		* timedown 倒计时时间
		* imageUrl 背景图
		* url 跳转链接
		*  -->
		<!-- #ifndef MP -->
		<mix-advert 
			ref="mixAdvert" 
			:timedown="4"
			imageUrl="/static/advert.jpg"
			:url="advertNavUrl"
		></mix-advert>
		<!-- #endif -->
		
		<!-- 顶部选项卡 -->
		<scroll-view id="nav-bar" class="nav-bar" scroll-x scroll-with-animation :scroll-left="scrollLeft">
			<view 
				v-for="(item,index) in tabBars" :key="item.id"
				class="nav-item"
				:class="{current: index === tabCurrentIndex}"
				:id="'tab'+index"
				@click="changeTab(index)"
			>{{item.name}}</view>
		</scroll-view>
		
		<!-- 下拉刷新组件 -->
		<mix-pulldown-refresh ref="mixPulldownRefresh" class="panel-content" :top="90" @refresh="onPulldownReresh" @setEnableScroll="setEnableScroll">
			<!-- 内容部分 -->
			<swiper 
				id="swiper"
				class="swiper-box" 
				:duration="300" 
				:current="tabCurrentIndex" 
				@change="changeTab"
			>
				<swiper-item v-for="tabItem in tabBars" :key="tabItem.id">
					<scroll-view 
						class="panel-scroll-box" 
						:scroll-y="enableScroll" 
						@scrolltolower="loadMore"
						>
						<!-- 
							* 新闻列表 
							* 和nvue的区别只是需要把uni标签转为weex标签而已
							* class 和 style的绑定限制了一些语法，其他并没有不同
						-->
						<view v-for="(item, index) in tabItem.newsList" :key="index" class="news-item" @click="navToDetails(item)">
							<text :class="['title', 'title'+item.type]">{{item.title}}</text>
							<view v-if="item.pics && item.pics.length > 0" :class="['img-list', 'img-list'+item.type, item.pics.length === 1 && item.type===3 ? 'img-list-single': '']">
								<view 
									v-for="(imgItem, imgIndex) in item.pics" :key="imgIndex"
									:class="['img-wrapper', 'img-wrapper'+item.type, item.pics.length === 1 && item.type===3 ? 'img-wrapper-single': '']"
								>
									<image class="img" :src="imgItem"></image>
									<view class="video-tip" v-if="item.videoSrc">
										<image class="video-tip-icon" src=""></image>
									</view>
								</view>
							</view>
							<!-- 空图片占位 -->
							<view v-else class="img-empty"></view>
							<view :class="['bot', 'bot'+item.type]">
								<text class="author">{{item.memberName}}</text>
								<text class="time">{{item.createTime}}</text>
							</view>
						</view>
						
						<!-- 上滑加载更多组件 -->
						<mix-load-more :status="tabItem.loadMoreStatus"></mix-load-more>
					</scroll-view>
				</swiper-item>
			</swiper>
		</mix-pulldown-refresh>
		
	</view>
</template>

<script>
	import mixAdvert from '@/components/mix-advert/vue/mix-advert';
	import json from '@/json'
	import Api from '@/common/api';
	import mixPulldownRefresh from '@/components/mix-pulldown-refresh/mix-pulldown-refresh';
	import mixLoadMore from '@/components/mix-load-more/mix-load-more';
	let windowWidth = 0, scrollTimer = false, tabBar;
	export default {
		components: {
			mixPulldownRefresh,
			mixLoadMore,
			mixAdvert
		},
		data() {
			return {
				tabCurrentIndex: 0, //当前选项卡索引
				scrollLeft: 0, //顶部选项卡左滑距离
				enableScroll: true,
				  pageNum:1,
				  pages:1,
				tabBars: [],
			}
		},
		computed: {
			advertNavUrl(){
				let data = {
					title: '测试跳转新闻详情',
					author: '测试作者',
					time: '2019-04-26 21:21'
				}
				return `/pages/details/details?data=${JSON.stringify(data)}`;
			} 
		},
		async onLoad() {
			// 获取屏幕宽度
			windowWidth = uni.getSystemInfoSync().windowWidth;
		// 	this.loadTabbars();
			   let params = {};
                          let tabList1 =  await Api.apiCall('get',Api.cms.subjectCategoryList,params);
		               let tabList =tabList1.records;
		                  tabList.forEach(item=>{
        					item.newsList = [];
        					item.loadMoreStatus = 0;  //加载更多 0加载前，1加载中，2没有更多了
        					item.refreshing = 0;
        				})
        				this.tabBars = tabList;
        				this.loadNewsList('add');


		},
		onReady(){
			/**
			 * 启动页广告 使用文档（滑稽）
			 * 1. 引入组件并注册 
			 * 		import mixAdvert from '@/components/mix-advert/vue/mix-advert';
			 *      components: {mixAdvert},
					 <!-- #ifndef MP -->
						<mix-advert 
							ref="mixAdvert" 
							:timedown="4"
							imageUrl="/static/advert.jpg"
							:url="advertNavUrl"
						></mix-advert>
					<!-- #endif -->
			 * 	2. 调用组件的initAdvert()方法进行初始化
			 * 
			 *  初始化的时机应该是在splash关闭时，否则会造成在app端广告显示了数秒后首屏才渲染出来
			 */
			// #ifndef MP
			this.$refs.mixAdvert.initAdvert();
			// #endif
		},
		methods: {
			/**
			 * 数据处理方法在vue和nvue中通用，可以直接用mixin混合
			 * 这里直接写的
			 * mixin使用方法看index.nuve
			 */
			//获取分类
			loadTabbars(){
				let tabList = json.tabList;
				tabList.forEach(item=>{
					item.newsList = [];
					item.loadMoreStatus = 0;  //加载更多 0加载前，1加载中，2没有更多了
					item.refreshing = 0;
				})
				this.tabBars = tabList;
				this.loadNewsList('add');
			},
			//新闻列表
			async loadNewsList(type){
				let tabItem = this.tabBars[this.tabCurrentIndex];

				  let params = {'pageNum':this.pageNum,'categoryId':tabItem.id};
				  let subjectList =   await Api.apiCall('get',Api.cms.subjectList,params);
				//type add 加载更多 refresh下拉刷新
				if(type === 'add'){
					if(tabItem.loadMoreStatus === 2){
						return;
					}
					tabItem.loadMoreStatus = 1;
				}
				// #ifdef APP-PLUS
				else if(type === 'refresh'){
					tabItem.refreshing = true;
				}
				// #endif
				
            this.pages=subjectList.pages;
					let list = subjectList.records;
					tabItem.newsList = list ;
						tabItem.newsList = tabItem.newsList.concat(list);

						console.log(type);
					if(type === 'refresh'){
					  let params1 = {'pageNum':1,'categoryId':tabItem.id};
                    				  let subjectList1 =   await Api.apiCall('get',Api.cms.subjectList,params1);

                        					tabItem.newsList = subjectList1.records;
					}

					//下拉刷新 关闭刷新动画
					if(type === 'refresh'){
						this.$refs.mixPulldownRefresh && this.$refs.mixPulldownRefresh.endPulldownRefresh();
						// #ifdef APP-PLUS
						tabItem.refreshing = false;
						// #endif
						tabItem.loadMoreStatus = 0;
					}
					//上滑加载 处理状态
					if(type === 'add'){
					console.log(tabItem.newsList.length);
						tabItem.loadMoreStatus = tabItem.newsList.length > subjectList.total ? 2: 0;
					}

			},
			//新闻详情
			navToDetails(item){

				let url = item.videoSrc ? 'videoDetails' : 'details'; 

				uni.navigateTo({
					url: `/pages/details/${url}?id=${item.id}`
				//	url: `/pages/details/${url}?data=${JSON.stringify(data)}`
				})
			},
			
			//下拉刷新
			onPulldownReresh(){

			      this.pageNum=1;

				this.loadNewsList('refresh');
			},
			//上滑加载
			loadMore(){
				if(this.pages>this.pageNum){
				  this.pageNum=this.pageNum+1;
				}

				this.loadNewsList('add');
			},
			//设置scroll-view是否允许滚动，在小程序里下拉刷新时避免列表可以滑动
			setEnableScroll(enable){
				if(this.enableScroll !== enable){
					this.enableScroll = enable;
				}
			},

			//tab切换
			async changeTab(e){
				  this.pageNum=1;
				if(scrollTimer){
					//多次切换只执行最后一次
					clearTimeout(scrollTimer);
					scrollTimer = false;
				}
				let index = e;
				//e=number为点击切换，e=object为swiper滑动切换
				if(typeof e === 'object'){
					index = e.detail.current
				}
				if(typeof tabBar !== 'object'){
					tabBar = await this.getElSize("nav-bar")
				}
				//计算宽度相关
				let tabBarScrollLeft = tabBar.scrollLeft;
				let width = 0; 
				let nowWidth = 0;
				//获取可滑动总宽度
				for (let i = 0; i <= index; i++) {
					let result = await this.getElSize('tab' + i);
					width += result.width;
					if(i === index){
						nowWidth = result.width;
					}
				}
				if(typeof e === 'number'){
					//点击切换时先切换再滚动tabbar，避免同时切换视觉错位
					this.tabCurrentIndex = index; 
				}
				//延迟300ms,等待swiper动画结束再修改tabbar
				scrollTimer = setTimeout(()=>{
					if (width - nowWidth/2 > windowWidth / 2) {
						//如果当前项越过中心点，将其放在屏幕中心
						this.scrollLeft = width - nowWidth/2 - windowWidth / 2;
					}else{
						this.scrollLeft = 0;
					}
					if(typeof e === 'object'){
						this.tabCurrentIndex = index; 
					}
					this.tabCurrentIndex = index; 
					
					
					//第一次切换tab，动画结束后需要加载数据
					let tabItem = this.tabBars[this.tabCurrentIndex];
					if(this.tabCurrentIndex !== 0 && tabItem.loaded !== true){
						this.loadNewsList('add');
						tabItem.loaded = true;
					}
				}, 300)
				
			},
			//获得元素的size
			getElSize(id) { 
				return new Promise((res, rej) => {
					let el = uni.createSelectorQuery().select('#' + id);
					el.fields({
						size: true,
						scrollOffset: true,
						rect: true
					}, (data) => {
						res(data);
					}).exec();
				});
			},
		}
	}
</script>

<style lang='scss'>
	
	page, .content{
		background-color: #f8f8f8;
		height: 100%;
		overflow: hidden;
	}

	/* 顶部tabbar */
	.nav-bar{
		position: relative;
		z-index: 10;
		height: 90upx;
		white-space: nowrap;
		box-shadow: 0 2upx 8upx rgba(0,0,0,.06);
		background-color: #fff;
		.nav-item{
			display: inline-block;
			width: 150upx;
			height: 90upx;
			text-align: center;
			line-height: 90upx;
			font-size: 30upx;
			color: #303133;
			position: relative;
			&:after{
				content: '';
				width: 0;
				height: 0;
				border-bottom: 4upx solid #007aff;
				position: absolute;
				left: 50%;
				bottom: 0;
				transform: translateX(-50%);
				transition: .3s;
			}
		}
		.current{
			color: #007aff;
			&:after{
				width: 50%;
			}
		}
	}

	.swiper-box{
		height: 100%;
	}

	.panel-scroll-box{
		height: 100%;
		
		.panel-item{
			background: #fff;
			padding: 30px 0;
			border-bottom: 2px solid #000;
		}
	}
	
	/**
	 * 新闻列表 直接拿的nvue样式修改，,
	 * 一共需要修改不到10行代码, 另外px需要直接修改为upx，只有单位不一样，计算都是一样的
	 * 吐槽：难道不能在编译的时候把nuve中的upx转为px? 这样就不用修改单位了
	 */
	.video-wrapper{
		width: 100%;
		height: 440upx;
		.video{
			width: 100%;
		}
	}
	
	view{
		display:flex;
		flex-direction: column;
	}
	.img{
		width: 100%;
		height: 100%;
	}
	.news-item{
		position:relative;
	}
	/* 修改结束 */
	
	/* 新闻列表  emmm 仅供参考 */
	.news-item{
		width: 750upx;
		padding: 24upx 30upx;
		border-bottom-width: 1px;
		border-color: #eee;
		background-color: #fff;
	}
	.title{
		font-size: 32upx;
		color: #303133;
		line-height: 46upx;
	}
	.bot{
		flex-direction: row;
	}
	.author{
		font-size: 26upx;
		color: #aaa;
	}
	.time{
		font-size: 26upx;
		color: #aaa;
		margin-left: 20upx;
	}
	.img-list{
		flex-shrink: 0;
		flex-direction: row;
		background-color: #fff;
		width: 220upx;
		height: 140upx;
	}
	.img-wrapper{
		flex: 1;
		flex-direction: row;
		height: 140upx;
		position: relative;
		overflow: hidden;
	}
	.img{
		flex: 1;
	}
	.img-empty{
		height: 20upx;
	}
	
	/* 图在左 */
	.img-list1{
		position:absolute;
		left: 30upx;
		top: 24upx;
	}
	.title1{
		padding-left: 240upx; 
	}
	.bot1{
		padding-left: 240upx; 
		margin-top: 20upx;
	}
	/* 图在右 */
	.img-list2{
		position:absolute;
		right: 30upx;
		top: 24upx;
	}
	.title2{
		padding-right: 210upx; 
	}
	.bot2{
		margin-top: 20upx;
	}
	/* 底部3图 */
	.img-list3{
		width: 700upx;
		margin: 16upx 0upx;
	}
	.img-wrapper3{
		margin-right: 4upx;
	}
	/* 底部大图 */
	.img-list-single{
		width: 690upx;
		height: 240upx;
		margin: 16upx 0upx;
	}
	.img-wrapper-single{
		height: 240upx;
		margin-right: 0upx;
	}
	
	.video-tip{
		position: absolute;
		left: 0;
		top: 0;
		display: flex;
		align-items: center;
		justify-content: center;
		width: 100%;
		height: 100%;
		background-color: rgba(0,0,0,.3);
	}
	.video-tip-icon{
		width: 60upx;
		height:60upx; 
	}
</style>
